Resonator-dome job



F. W. MINOR.

RESONATOR DOME FOR R-EPRODUCEBS.

APPLICATION FILED JUNEZ. 1920.

1,875,408. I v Patented Apr. 19, 1921.

Jwmk mm'nor,

. UNITED STATES PATENT OFFICE.

FRANK W. MINOR, 0F RICHMOND, VIRGINIA.

f -RESONATOR-DOME ron. nnrnonuonns.

', a plication filed June 2, 1920. Serial m5. 385,998.

To allwho'mz'tmay'concem; p

Be it known that I, FRANK W. MINOR, a. citizen of the United States, and a resident of Richmond, in the county of Henrico and State of Virginia, have invented certain new and useful Improvements in Resonator- Domes for Reproducers, of which the following is a specification.

This invention relates to the reproducers of phonographs and similar machines and has for its object the provision of simple, inexpensive means whereby the sound vibrations will be amplified and increased resonance imparted thereto, so that practically all the tones, which would otherwise be lost, through the absence of a confined air chamber will be preserved; the openings in the outer dome shell through which the stylus arm passes acting as an equalizer vent or escape for the air cushion. The object of the invention is attained in such a device as is illustrated in the accompanying drawings and it consists in certain novel features which will be hereinafter first fully described and then particularly pointed out in the appended claims.

In the drawings- Figure 1 is an elevation of a resonator compound dome embodying the invention; and

Fig. 2 is a central longitudinal section of the same.

The reproducer shell 1 is of the usual form and has a central outlet nipple 2 to be coupled to the usual tone arm. The diaphragm 3 is secured in the shell by the gasket rings 4 and the stylus arm 5 is secured to the diaphragm in the usual or any preferred manner.

In carrying out my invention, I employ a dome or bell 6, which may be of any suitable material, but will preferably be of resonant sheet metal. As shown clearly in Fig. 2, this bell is of cylindrical or tubular form, open at one end and closed at the other end; it being understood of course that it is not intended to be limited to this particular shape of dome. Atits open end the bell is provided with an annular flange 7, which fits within the shell or rim or wall of the reproducer frame and is secured therein by a clamping threaded ring 8, a slot 9, being formed in the side of the bell adjacent its open end to accommodate the stylus arm. Within the bell or dome 6, I provide one or more supplemental bells or domes 10, which i Specification of Letters Patent.

Patented Apr. 19, 1921.

are arranged concentrically, the several bells being equidistantly spaced and slots or notches 11, being formed in the inner or supplemental bells to accommodate the stylus arm. Like the outer inclosing bell, the inner bells have'an open end and a closed end, the open ends of all the bells being presented to the diaphragm. The inner bells are supported by the outer bell, the illustrated supporting means consisting of a bolt 12, inserted centrally through the crowns of all the bells and equipped with a nut 13 on its inner end while spacing collars 14 are mounted upon the bolt between the bells.

It will be readily seen that the air in front of the diaphragm, except the small volume which may pass through the slots 9 and 11, is confined within the bells and will vibrate in unison with the diaphragm so as to strengthen the sound waves sent through the tone arm by the diaphragm. The inner bells are suspended centrally. so that their walls are free to vibrate in response to and in unison with reflected sound waves and co6rdinate with the vibrations of the diaphragm.

Having thus fully described my invention, What I claim as new and desire to secure by Letters Patent of the United States, is

1. A sound reproducer provided on its open front side with a resonator comprising a tubular body having a closed front end and having an open rear end presented to and secured upon the reproducer and cover ing the front side of the same.

2. A resonator for sound reproducers, consisting of a plurality of concentric bells to be secured upon the reproducer and having open ends to be presented to the reproducer, the outer ends of all the bells being closed and the inner end of the outermost bell being covered by the reproducer.

3. The combination with a sound reproducer, of a resonant tubular body secured to and having its end covered by the reproducer, and supplemental resonant bodies carried by and within the first mentioned body, the outer ends of all the bodies being closed.

4. The combination with a sound reproducer, of a bell secured to the front side of the reproducer, and resonant members within the bell mounted for free vibration, the outer end of the bell being closed and the inner end thereof entirely covered by the reproducer.

5. The combination with a sound reproducer, of a bell having a closed outer end and having an open inner end secured to and covered by the reproducer, a plurality of supplemental bells arranged concentrioally within the first mentioned bell and having closed outer ends and open inner ends presented to the reproducer, and means passing centrally through the closed outerends of all the bells to secure them together 7 10 in fixed spaced relation.

and having an open inner end secured to and covered by the reproducer, a plurality of supplemental bells arranged concentrically Within the first mentioned bell and having closed outer ends and open inner ends; all the bells being provided in their Walls at their inner ends with slots for the passage of a stylus arm, a post inserted axially through the'outer closed ends of the bells, and means on the post to secure the bells in fixed spaced relation.

FRANK W. MINOR. 

